1. Field of the Invention
The invention relates to a display system, and in particular to a display system capable of preventing banks (non-uniform color), water waves and high frequency noise.
2. Description of the Related Art
Liquid crystal displays (LCDs) are used in a variety of applications, including calculators, watches, color televisions, computer monitors, and many other electronic devices. Active-matrix LCDs are a well known type of LCD. In a conventional active matrix LCD, each picture element (or pixel) is addressed using a matrix of thin film transistors (TFTs) and one or more capacitors. The pixels are arranged and wired in an array having a plurality of rows and columns.
To address a particular pixel, the switching TFTs of a specific row are switched “on” (i.e., charged with a voltage), and data voltage is sent to the corresponding column. Since other intersecting rows are turned off, only the capacitor at the specific pixel receives the data voltage charge. In response to the applied voltage, the liquid crystal cell of the pixel changes its polarization, and thus, the amount of light reflected from or passing through the pixel changes. In liquid crystal cells of a pixel, the magnitude of the applied voltage determines the amount of light reflected from or passing through the pixel.
Generally, boosting devices are required for LCDs in order to provide a higher voltage to drive display panels therein. Most commonly, a charge pump is used and voltages generated thereby control the magnitude of the respective gate line signal applied to each of gate line, the magnitude of the Vcom signal applied to the common electrode (COM), and the Gammar circuit to generate different gray values. Thus, a charge pump providing stable high voltage is important for high display quality.